The present invention relates to a method and apparatus for the continuous manufacture of packing containers comprising a rigid casing and an inner thin baglike container.
Beverages, such as juice and wine, are most frequently packed in glass bottles which, however, require energy to manufacture, are breakable and heavy which renders the transport of the packages more expensive. Another disadvantage is that glass bottles, if returnable, are expensive to wash, collect and return and, if non-returnable, create considerable environmental problems. There is consequently a great need for a light and inexpensive package which is at the same time environmentally acceptable and provides satisfactory protection for the contents.
The present invention relates to a method for the manufacture of such a package, which method is characterized in that a double web of thin packing material, e.g. plastic film or a laminate comprising several material layers, is advanced by an intermittent or continuous movement. The double web comprises two layers of packing material and the material layers in the double web are sealed to one another along narrow first sealing joints arranged in pairs and extending substantially in transverse direction of the double web. One or more mandrels are introduced between the said narrow first sealing joints arranged in pairs and are inserted so that with their front parts they extend up to or close to the longitudinal edge of the double web adjacent first sealing joints are made to coincide in pairs or to overlap each other with their sealing joints facing one another. The mandrels are withdrawn from the double web, whose free longitudinal sealing joints are then joined together in a second longitudinal sealing joint to form a tube of varying cross-section; tube is filled with the intended contents by a filler pipe introduced into the tube. The tube is divided into individually filled and closed containers by third sealing joints located across the tube, which extend from the first to the said second sealing joints. The filled and closed tube portions are severed from one another by cuts through the third sealing joints, and the severed baglike containers thus obtained are introduced into the rigid casing and fixed there.